import random
stu = [ ]
for c in 'ABCDEFGHIJ':
    yz = (c, random.randint(40,100))
    stu.append(yz)

print(stu)
score = sum( [s[1] for s in stu])
print('平均分:',score/len(stu))
stu2 = [s for s in stu if s[1]<60]
print('不及格人数：',len(stu2))

